1. Field of the Invention
The present invention relates to brake bleeder valves, and more particularly pertains to a new and improved brake bleeder valve which includes a ball check valve to enable bleeding of brakes by a single individual. Hydraulic systems on brake vehicles typically include a master cylinder mounted beneath the hood of the vehicle and a wheel cylinder formed in the brake caliper at each wheel of the vehicle. Upon depressing the brake pedal, the master cylinder transmits fluid pressure to the wheel cylinder, which moves a piston received therein to apply the vehicle brakes. Upon servicing such hydraulic brakes, air frequently becomes trapped in the brake lines and in the wheel cylinders. In order to enable trapped air to be expelled, a brake bleeder valve is typically provided at each wheel cylinder Conventionally, the bleeding of air from such hydraulic brake systems has been a two man operation. A first individual repeatedly depresses and releases the brake pedal and a second individual tightens and loosens the brake bleeder valve at the wheel cylinder as the brake pedal is depressed and released. When the brake pedal is being depressed, it is necessary to release the brake bleeder valve, to allow the trapped air to be exhausted. Before release of the brake pedal, the bleeder valve must be tightened, to prevent air from being drawn into the wheel cylinder, as the piston is retracted. This tedious and time consuming procedure must be repeated at each wheel cylinder in order to complete the process. In order to allow a brake bleeding process by a single individual, the present invention provides a new and improved brake bleeder valve which utilizes a check valve to prevent air from being inducted into the wheel cylinder when the brake pedal is released.
2. Description of the Prior Art
Various types of brake bleeder valves are known in the prior art. A typical example of such a brake bleeder valve is to be found in U.S. Pat. No. 3,913,619, which issued to M. Aulner et al on Oct. 21, 1975. This patent discloses an air bleeder valve assembly for hydraulic systems, mountable in the bleeder outlet and containing a check valve, the spring of which is held in place by a spring retainer exerting a constant pressure against the walls of an air bleeder passage through a roll pin. U.S. Pat. No. 4,318,460, which issued to A. Kosinski on Mar. 9, 1982, discloses a fluid operated brake including a pressurized fluid chamber with a single supply and bleed fitting. The pressurized fluid chamber can be a wheel cylinder of a drum brake or a caliper housing of a disc brake. The chamber has a single port therein in which a fitting is mounted, the fitting being designed to supply fluid under pressure to the chamber and to bleed gas, commonly air from the chamber. With only a single opening for the chamber, one boss can be eliminated to save weight, and machining of that boss is also eliminated to save costs U.S. Pat. No. 4,474,272, which issued to D. Omlie on Oct. 2, 1984, discloses a wheel cylinder bleed passage incorporated in the brake fluid connector mounting bolt and including a ball check valve assembly for bleeding purposes. U.S. Pat. No. 4,664,451, which issued to S. Sakaguchi et al on May 12, 1987, discloses an air bleeder for a fluid braking system which operates to reduce a braking liquid pressure supplied to a wheel cylinder at a given proportion to a braking liquid pressure supplied to a front wheel cylinder as a braking liquid pressure is supplied from a master cylinder. An air bleeder is disclosed for use with such a fluid system, and includes a plunger slidably received in a bore formed in a housing in which a plate is fitted to serve as a stop member and an end of the plunger is maintained in abutment against the plate when operative. The air bleeder comprises an air bleeding path formed in a plate so as to extend across the area of contact between the plate and the plunger to maintain the space in communication with the fluid passage.
While the above mentioned devices are suited for their intended usage, none of these devices disclose a brake bleeder valve including an enlarged diameter spherical seat formed in a hose fitting at an upper end of the body of the valve, and having a spring urged ball check valve received therein to allow fluid flow through a central passage of the valve in only one direction. Additionally, none of the aforesaid devices disclose the provision of an O-ring received around the body of a bleeder valve and having an upper surface in contact with an abutment face formed on a lower end of a hexagonal wrench flat portion. Additional features of the present invention, not disclosed by the aforementioned prior art devices, include the provision of a tubular insert to form an annular abutment face for the check valve spring and the provision of a dust cap having a hemispherical top portion terminating in a cylindrical portion forming a radially inwardly extending annular flange defining a bottom end opening dimensioned for frictional engagement over the hose fitting at the upper end of the bleeder valve. Inasmuch as the art is relatively crowded with respect to these various types of brake bleeder valves, it can be appreciated that there is a continuing need for and interest in improvements to such brake bleeder valves, and in this respect, the present invention addresses this need and interest.